C.O.R.N. Newsletter 2013-40

Dates Covered: 
December 4, 2013 - December 18, 2013
Editor: 
Greg LaBarge

Seed Treatments for 2014 Soybean

If we could predict or know that the planting season during 2014 would be like it was in 2012 (the dry spring), then we would say don’t treat your seed at all.  But if the season is like this past year, wet, the combinations of seed treatments did a much better job and at the higher rates.  There have been lots of questions over the past few days on what fungicides to apply; what rates to use; and are insecticides always necessary.  Here we try to parse it all out for you.

Metalaxyl (Numerous companies) & Mefenoxam (Syngenta):

These products are targeted for most of the water molds.  Damping-off, seed rot, and poor stands are the primary symptoms that occur in the field, but at the end of the year – yield benefits can be measured.  The two active ingredients are applied at totally different rates.  For Metalaxyl – typical rates are 0.2 (low), 0.75 (medium) or 1.5 (high) fl oz/cwt and mefenoxam is applied at 0.16 (low), 0.32 (medium), and 0.64 (high) fl oz/cwt. 

Our data from fields with optimum disease conditions, both at the research branches and on farm have shown that the higher rates provide for significantly higher stands (thus no replant), as well as higher yield at the end of the season.   Some companies have begun to drop the rate, which is fine for other states and areas of Ohio where the soils are better drained and there is little pressure from Phytophthora. 

However, for producers that farm poorly drained fields, no-till, continuous soybean or soybean/corn rotation, and have a history of replant are the most likely to see the added benefit of higher rate of seed treatment.  Work with your seed dealer to figure out which active ingredient he has and then which rate is most appropriate for your field conditions and history. 

Strobilurins: 

Several active ingredients of this chemistry have been added to the seed treatments over the past few years.  They have a limited spectrum of activity, but for the most part they are contributing to better stands and yield under Ohio’s conditions.  Some of the strobilurins have activity towards some but not all of the Pythium spp.  This is giving an added benefit to the soils with poor drainage, no-till and where even with the high rate of metalaxyl or mefenoxam, control was not optimal. 

Some of the strobilurins are also good on Phomopsis, a fungal disease that is seed borne.  Seed lots with less 70% germination should not be planted, but those with 70 to 90% germination can see an improvement in germination when treated with pyraclostrobin (BASF) but not azoxystrobin (Syngenta) or trifloxystrobin (Bayer).  I have no idea why there is specificity here, but there is.

Fludioxinil (Syngenta):  This product is sold as Maxim and has and continues to have excellent activity towards Fusarium and Rhizoctonia as well as seed borne Phomopsis and Sclerotinia.

Sedexane (Syngenta):  Newer product and new mode of action on the market also has good activity towards Rhizoctonia.

Ipconazole (Valent):  Another new seed treatment compound that has good activity towards Fusarium and Rhizoctonia.

Penflufen (Bayer/Pioneer):  A new seed treatment compound targeted towards Rhizoctonia sold as EverGol Prime.

Insecticides (thiamethoxam [Syngenta], clothianidin [Bayer and Valent], and imidacloprid [Monsanto]): 

There are these three insecticides that are widely used as soybean seed treatments, usually in combination with one or more of the above fungicides.  They are labeled for numerous insects, including soil pests such as seedcorn maggot, white grub, and wireworm, and early season foliar insects such as soybean aphid and bean leaf beetle. 

However, our experience is that the only soil pest of significance on soybean in Ohio is seedcorn maggot, and then only when a green, living cover or manure is incorporated into the soil prior to planting.  This is the only scenario we have see seedcorn maggot issues.  None of the other soil pests appear to occur in Ohio on the crop.  Although these seed treatments will offer control of the foliar insects that are listed, they are seldom if ever needed. 

Although bean leaf beetles will occur on early planted soybeans, they are almost never reach economic levels, and even then, can always be controlled with a foliar insecticide spray following scouting.  If growers are planting soybean for seed or food grade purposes and have had problems with bean pod mottle virus, they might consider a seed treatment to potentially offer suppression of the virus, albeit it will not be controlled. 

With soybean aphids, growers should realize two things.  First, Ohio aphid populations are on a two year cycle, and few aphids are observed in even numbered years, which should be the case in 2014.  Second, most aphids show up in our fields in later June, not in May.  Thus, there are usually no aphids to “control” even in the odd numbered years early in the season.  At most, a grower might delay aphid population growth in mid-summer by a week when using a seed treatment.  But if conditions are right for aphids to achieve economic levels, a foliar treatment will still be necessary; you will still be paying for and making two insecticide treatments. 

Thus, growers should consider whether or not insecticide seed treatments are really necessary prior to spending the additional money for an insecticide treatment that perhaps is not necessary nor that effective.

What’s Enogen Corn?

I’ve received several questions recently concerning “Enogen corn”.  This is a special type of corn developed by Syngenta for ethanol production. It contains a transgene from a bacteria that produces alpha amylase, an enzyme that breaks down corn starch into sugar. Presently alpha amylase enzyme is added to corn in a liquid form during the ethanol production process.  Corn hybrids with the Enogen trait technology (i.e. Enogen corn) express alpha amylase enzyme directly in the corn kernel, eliminating the need for liquid alpha amylase in dry grind ethanol production. Various trade publications indicate that only 10-20% of an ethanol plant’s total corn supply would need to be Enogen grain to produce the alpha amylase required for breaking down corn starch to sugar.

According to Syngenta, use of the Enogen grain saves the cost of adding liquid enzymes, and   facilitates the processing of higher dry solids levels, increasing yield and throughput (http://www.syngenta.com/country/us/en/agriculture/seeds/corn/enogen/about/pages/enogen-trait-technology.aspx).  In addition Syngenta reports that use of Enogen grain results in measurable reductions in water, electricity and natural gas usage on a per gallon basis.

Enogen corn has been receiving attention locally because Syngenta recently announced it has signed a commercial agreement with Three Rivers Energy, LLC that operates the ethanol plant in Coshocton, Ohio, to use grain containing Enogen trait technology following the 2014 corn harvest. Syngenta has similar agreement with ethanol plants in other states.  Farmers who grow Enogen under contract may receive premiums of about 40 cents per bushel over other corn. A local farm publication indicates that about 12,000 acres will be under contract in Ohio for the first year.

Unlike other transgenic corns introduced for insect and herbicide tolerance, Enogen corn was specifically developed for industrial purposes – ethanol production. A number of organizations ranging from the North American Millers Assoc. to the Union of Concerned Scientists opposed USDA’s 2011 approval of Enogen hybrids. These organizations warned that mixing (comingling) of Enogen  corn with corn used for food could have significant adverse impacts on food product quality and performance, e.g. crumbling corn chips (resulting from starch breakdown caused by alpha amylase activity in Enogen grain).

Syngenta has established a stewardship program to prevent contamination of commodity grain by Enogen grain (http://www.syngenta.com/country/us/en/agriculture/seeds/corn/enogen/stewardship/pages/stewardship-protocols.aspx). Management practices that farmers under contract would be required to follow include planting buffers of non-Enogen corn around fields planted to Enogen corn, storing the Enogen grain in separate bins, and cleaning planters and combines between uses.

Syngenta indicates that the agronomic performance of hybrids containing Enogen trait technology is similar to conventional (non-Enogen hybrids) and that Enogen hybrids with insect and herbicide tolerance traits are available. I’m not aware of any university/extension tests that have evaluated the performance of hybrids with and without the Enogen trait.

Metaldehyde on Field Crops

The EPA has just established tolerances for the first time for metaldehyde for corn and soybean which will mean that molluscicides for slug control containing this product, such as Deadline MPs, should be available in the future for both corn and soybean in Ohio.  The re‑registration of metaldehyde approved earlier this year did not have those two crops on the label, and field crop growers were faced with the removal of metaldehyde products from their tool box.  In reality, metaldehyde never had tolerances for those two crops.  However, through work of the IR-4 program, a program that helps get products labeled for minor uses or in this case, minor uses on major crops, EPA has established tolerances for metaldehyde on corn and soybean as of last week.  We will keep growers informed when we see new product labels that should list both crops.

2013 Ohio Corn Performance Test: Regional Overviews

In 2013, 240 corn hybrids representing 28 companies and 33 commercial brands were evaluated in the Ohio Corn Performance Test (OCPT). Four tests were established in the Southwestern/West Central/Central (SW/WC/C) region and three tests were established in the Northwestern (NW) and North Central/Northeastern (NC/NE) regions (for a total of ten test sites statewide).  Hybrid entries in the regional tests were planted in either an early or a full season maturity trial. These test sites provided a range of growing conditions and production environments.

The 2013 growing season throughout much of Ohio was characterized by favorable conditions for corn growth and development.  Rainfall was generally below normal in May but was near normal to well above normal in June and July, during mid-to-late vegetation stages, pollination, and early grain fill. Near normal to below normal temperatures in July and August mitigated the impact of dry conditions in August and Sept. At most test sites, rainfall was below normal in Sept. and above normal in October. Persistent rains in October delayed harvest at several locations. A severe wind storm on July 10 resulted in widespread root lodging and some localized greensnap damage. Plants in most root lodged fields recovered within 1 to 2 weeks after this wind event. Stalk and root lodging at harvest was generally negligible. However lodging was greater at test sites harvested after storms on October 31 that were accompanied by strong winds. Disease and insect pests were not a significant factor at most test sites. At Washington CH, gray leaf spot was severe but appeared late in the season.

Record high yields were achieved at most test locations due to ample and timely rainfall and moderate temperatures which created near stress-free growing conditions for most of the growing season. Averaged across hybrid entries in the early and full season tests, grain yields in the Southwest and West Central region and the North Central and Northeast region were 239 bu/A, whereas yields in the Northwest region were 248 bu/A. At the Hebron and Upper Sandusky test sites in the SW/WC/C and NW regions, respectively, there were several hybrids with average yields of 300 bu/A or greater. Performance data for South Charleston in the SW/SC region and Bucyrus in the NC/NE region are not presented. At these sites, excessive rainfall (S. Charleston) and wind damage (Bucyrus) created variable field conditions resulting in inconsistent yields.

Tables 1 and 2 provide an overview of 2013 hybrid performance in the early maturity and full season hybrid trials by region. Averages for grain yield and other measures of agronomic performance are indicated for each region. In addition, the range in regional test site averages is shown in parentheses. Complete results are available online at: http://www.ag.ohio-state.edu/~perf/ and http://www.oardc.ohio-state.edu/corntrials/.

As you review 2013 test results, it’s important to keep the following in mind. Confidence in test results increases with the number of years and the number of locations in which the hybrid was tested. Avoid selecting a hybrid based on data from a single test site, especially if the site was characterized by abnormal growing conditions (like drought stress and record high temperatures). Look for consistency in a hybrid's performance across a range of environmental conditions.  Differences in grain moisture percentages among hybrids at harvest can provide a basis for comparing hybrid maturity.  Yield, % stalk lodging, grain moisture, and other comparisons should be made between hybrids of similar maturity to determine those best adapted to your farm. Results of the crop performance trials for previous years are also available online at:  http://www.ag.ohio-state.edu/~perf/archive.htm   

Table 1.   A regional overview of the early maturity 2013 Ohio Corn Performance Test.

 

Region

 

Entries

Grain Yield

(Bu/A)

Moisture

(%)

Lodging

(%)

Emergence

(%)

Final Stand

(plants/A)

Test Wt.

(lbs/bu)

SW/WC/C

67

234

(207-259)

18.4

(16.4-20.5)

0

(0-6)

96

(87-99)

37500

(33500-40900)

58.6

(54.6-61.5)

NW

67

246

(207-265)

17.3

(15.8-19.1)

2

(0-14)

96

(87-100)

36600

(30600-40800)

59.1

(54.9-61.3)

NE/NC

57

238

(222-255)

21.1

(17.5-24.0)

9

(0-45)

90

(75-96)

34900

(27200-38900)

55.6

(52.6-58.8)

 

Table 2.  A regional overview of the full season 2013 Ohio Corn Performance Test.

 

Region

 

Entries

Grain Yield

(Bu/A)

Moisture

(%)

Lodging

(%)

Emergence

(%)

Final Stand

(plants/A)

Test Wt.

(lbs/bu)

SW/WC/C

76

244

(224-262)

20.0

(18.3-23.6)

0

(0-1)

95

(87-99)

36200

(32700-41100)

58.0

(54.7-60.4)

NW

96

251

(217-273)

18.6

(16.5-20.8)

1

(0-10)

96

(88-99)

37100

(32600-41100)

58.8

(55.3-61.7)

NE/NC

61

240

(214-265)

23.7

(22.0-29.5)

6

(0-30)

93

(82-98)

35300

(31300-39700)

54.2

(51.3-58.6)

Updated Marestail Control Information

Ohio State University Extension and Purdue have partnered to publish a new fact sheet aimed at helping farmers battle herbicide-resistant marestail and its yield-reducing affects on soybeans.

Marestail, also referred to as horseweed, primarily emerges in late summer into fall and again from late-March through June in both Indiana and Ohio. The weed competes with soybean plants for soil nutrients, space and water. Mature marestail also can hinder soybean harvest, and it doesn't respond to treatment from one of the most commonly used herbicides.

"Most populations of marestail in Ohio and Indiana are resistant to glyphosate, and will not be controlled by burndown or post-emergence applications of glyphosate alone," said Mark Loux, Ohio State Extension weed scientist.

Glyphosate resistance means farmers need to pay extra special attention to herbicide application timing so they can try to control marestail during early growth stages when it's most treatable. It also means soybean growers likely will need to use a cocktail of other herbicides to achieve marestail control.

Loux and Purdue Extension weed scientist Bill Johnson hope to make navigating marestail control a little bit easier with their new fact sheet, "Control of Marestail in No-Till Soybeans," which is available for free download at:

OSU Extension Weed Science - https://agcrops.osu.edu/specialists/weeds

The fact sheet includes information about marestail biology, soybean yield loss, herbicide resistance and steps for controlling and managing the weed.

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About the C.O.R.N. Newsletter

C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.